Slice the leeks into thick rounds and rinse well to remove dirt.

Steam or boil leeks for 5–7 minutes until tender, then drain and cool.

In a bowl, whisk olive oil, lemon juice, mustard, salt, and pepper.

Add the chickpeas and cooked leeks to the bowl.

Toss gently to coat.

Sprinkle with parsley and serve chilled or at room temperature.